For example, as disclosed in Japanese Unexamined Patent Application Publication No. 2000-110462, a window screen configured to be installed at a building opening and provided with a function of a blind capable of varying an angle of inclination of slats is already known.
A screen apparatus including the window screen includes a net or a sheet-type screen to be wound by a winding shaft, a number of slats configured to be attached to one surface side of the screen substantially at regular intervals so as to be freely tiltable, and being coupled at free end sides thereof to a flexible coupling member such as the net at substantially same intervals as intervals of attachment to the screen, and a winding shaft configured to wind the screen by rotation thereof together with the slats, the flexible coupling member and the like attached thereto, and the above-described slats are configured to be tiltable at the free end sides thereof with respect to the screen in a state in which the above-described screen is fed out from the winding shaft and extended in a tensed manner at the building opening.
Japanese Unexamined Patent Application Publication No. 6-88469also discloses the same type.
In the screen apparatus of this type, when extending the flexible coupling member or the like such as the screen, and the slats and the net wound around the winding shaft at the building opening in a tensed manner by rewinding from the winding shaft, the respective slats needs to be capable of retaining a light-shielding state by lying along the screen until a bottom bar provided at a lower end of the screen or the like reaches a lower frame of a screen frame for achieving light-shielding with the slats, and the slats needs to be capable of tilting at the free end sides thereof to a suitable angle of inclination with respect to the screen at least by some operation after the above-described bottom bar reaches the lower frame of the screen frame. In addition, when tilting the slats to a suitable angle of inclination at free end sides thereof in a state in which the above-described bottom bar reaches the lower frame of the screen frame, it is desired that the operation thereof can be performed easily and stably to achieve adjust the angle of inclination of the slats freely while keeping the above-described bottom bar constantly not to separate from the lower frame of the screen frame for preventing rattling due to wind the like or entry of insects.
When a configuration of the screen apparatus disclosed in Japanese Unexamined Patent Application Publication No. 2000-110462 is considered from such a point of view, in the screen apparatus, a single bottom bar 8 is attached between a lower end of a screen 4 to which one end of each of a number of slats 5 is attached, which is wound around a freely rotatable winding shaft 2 and a lower end of a flexible coupling member 6 to which the other end of each of a number of the slats 5 is attached. Therefore, it is superior in terms of simple configuration, but there are following problems caused by this configuration.
In other words, as described above, when a configuration in which the single bottom bar 8 is attached between the lower end of the screen 4 and the lower end of the flexible coupling member 6 is employed, it becomes difficult to adjust lengths of the screen and the flexible coupling member easily in accordance with an opening length of the building opening in a vertical direction to which the screen apparatus is installed. For example, it is difficult to keep the bottom bar attached to the lower end of the screen in stable contact with the lower frame of the screen frame irrespective of an inclined posture of the above-described slats and suppress occurrence of rattling due to wind or the like or significant disfigurement due to formation of a gap between the bottom bar and the above-described lower frame. In the case where an insect preventing net is used as the above-described screen, and the screen apparatus is used as a window screen for a protection from insects, if the gap is formed between the above-described lower frame and the bottom bar, it works as an insect entrance route. In the case where the screen and the flexible coupling member are longer than an opening length of the building opening in the vertical direction, the inclined posture of the slats becomes unstable due to a sagging generated thereby.
As described above, the reason why the gap tends to be formed between the above-described lower frame and the bottom bar is that the posture of the bottom bar 8 is unstable due to wind or the like as a result that the configuration is simplified by attaching the single bottom bar 8 between the lower ends of the screen 4 and the flexible coupling member 6 wound around the winding shaft 2. Therefore, as illustrated in FIGS. 20(A) and (B), an attempt is made to stabilize the posture of the bottom bar 8 by forming a contact surface 8a of the bottom bar 8 with respect to the lower frame 9 into an arcuate shape. However, in this case as well, there are disadvantages such that a gap is formed between the bottom bar 8 and the lower frame 9 unless the screen apparatus is installed in site with the lengths of a pair of the screen 4 and the flexible coupling member 6 adapted to a vertical dimension of an inside of the screen frame and, in addition, rattling of the bottom bar 8 due to wind or the like cannot be prevented by a guide or the like.